Apple on Tuesday pulled both 500px and ISO500 due to a claimed breach of App Store rules regarding pornographic material, effectively cutting off new user access to the popular photo sharing apps tailored to professional photographers and artists.

The apps' removal, as reported by TechCrunch, came early Tuesday morning following a late-night discussion between 500px and Apple over an app update that was flagged for violating App Store policy. The app has been in the App Store for over 16 months.

500px is a well-designed and long-standing app accompaniment to the online photography community of the same name. The company's Chief Operating Officer Evgeny Tchebotarev said the iOS versions have amassed over one million downloads, with 500px yielding almost one million, while the newly acquired ISO500 accounts for over 200,000.

When an update to the flagship 500px was submitted to Apple a few days ago, a reviewer flagged the app for objectionable content. Ultimately, the company found it was too easy to find nude photos through the built-in search function and consequently pulled the app this morning.

"The app was removed from the App Store for featuring pornographic images and material, a clear violation of our guidelines," an Apple spokesman said in a statement to The Next Web. "We also received customer complaints about possible child pornography. Weve asked the developer to put safeguards in place to prevent pornographic images and material in their app."

According to Tchebotarev, 500px already comes with a safeguard against the unwanted search of nude photos. When new users download the app, the default settings are set to "safe search" mode that filters out nude images. In order to lift safe search, users must leave the app and make changes to their account settings on the company's desktop website.

Some people are mature enough to see these photos, Tchebotarev said, but by default its safe.

Further, 500px does not allow photos deemed "pornographic" in nature onto its service. Tchebotarev noted that all nude photos are artistic and can be defined as art, not pornography.